Nigeria's former national security adviser Sambo Dasuki , centre, arrives for a hearing on charges of possessing weapons illegally, at the Federal High Court in Abuja, Nigeria. Monday, Dec. 14, 2015, Nigeria’s former national security adviser says $47 million was withdrawn in cash from the Central Bank on the order of former President Goodluck Jonathan and was used to pay delegates at a party presidential nomination conference.

LAGOS, NIGERIA; and JOHANNESBURG, SOUTH AFRICA — When Lai Mohammed assumed his new job as Nigeria’s Minister of Information and Culture in November, he immediately noticed something awry in the salaries budget of his government agencies. The payroll was swollen with mysterious employees – some 400 – all claiming to have jobs that, officially, did not exist.

That, in itself, was hardly news in Nigeria, where Mr. Mohammed himself calmly announced last week that a group of 55 high-ranking government officials had stolen $9 billion – or a quarter of the country’s yearly budget – from the treasury between 2006 and 2013.

“Of course we dismissed these officers and we even handed them over to the police,” he told journalists over the weekend. The message: For those stealing from the government, the time for impunity was over.

Indeed, since Mohammed’s boss – President Muhammadu Buhari – took office in May last year on a campaign of clean government, he has made clear that he will no longer tolerate the graft that has siphoned billions from Africa’s largest economy, exacerbating poverty and hobbling the country's fight against Boko Haram militants. Mr. Buhari has demanded public agencies open themselves to closer financial scrutiny, put public works on ice to scrutinize contracts, and is overhauling management of the state oil company – one of the biggest sources of graft.

“This crusade is a witch hunt and a charade,” says Samuel Adetula, a construction worker in Lagos. “This money they have collected, what have they done with it?”

Political tensions

Opponents of Buhari point to the recent high-profile arrests of Olisa Metuh, national spokesman for the opposition People’s Democratic Party, and Sambo Dasuki, national security adviser to former president Goodluck Jonathan, as proof that the targets are unapologetically and overtly political.

“There is nothing political about the trial,” says Wilson Uwujaren, spokesman for the Economic and Financial Crimes Commission. “Have any of those arraigned in court claimed they have not committed the offenses for which they were charged?”

Some outsiders agree. If much of the blame for the corruption rot is going to the former government, they point out, it is because that is who was in charge of the bank accounts as the money mysteriously drained out of them.

“People who occupied some position of trust in the previous government … have denied many Nigerians education, health, and risked the security of this country by misappropriating the funds meant to procure arms for the soldiers combatting Boko Haram insurgents,” says Adetokunbo Mumuni, executive director of the Socio-Economic Rights and Accountability Project, a human rights group. “They deserve to be prosecuted and jailed.”

'Cautiously optimistic'

If the president’s tactics are dangerous, it may not be because of who he is prosecuting, but how.

While Mr. Dasuki, for example, was granted bail, has been held in jail without access to his lawyers since December, raising concerns that Buhari is slipping back into outlooks he held when he was a military dictator 30 years ago.

“I cannot accept that human rights be subsumed under a war for corruption,” says Ebun Olu-Adegboruwa, a Lagos-based lawyer. “To say that people will no longer be granted bail in Nigeria because they are facing corruption charges is wrong.”

Despite uncertainties over Buhari’s respect for judicial independence, the situation in Nigeria looks better than it has in years, says Samuel Kaninda, the West Africa coordinator for the international anti-corruption watchdog Transparency International. In the organization’s most recent survey of citizens’ perceptions of corruption – carried out largely before Buhari took office – three-quarters of Nigerians said they believed corruption had been on the rise in their country over the previous year, and 78 percent said they believed the government was doing a poor job of stopping it.

Now, he says, there is an increasing belief that the fight against corruption has a new weapon – political will.

“We feel cautiously optimistic,” he says. “The first few steps have been in the right direction – now we must wait to see if the trend continues, and how the presidency handles cases of individuals not necessarily associated with the old regime.”